Sadiron sole plate and method of making



Nov. 29, 1938. H. c. WRIGHT 2,133,720

SADIRON SOLE PLATE AND METH OD OF MAKING Filed Sept. a, less 13 19 1a 1aZ1 7 Q 2.5 I I g Patented Nov. 29, 1938 SADIRON SOLE PLATE ANDMETBOD OFMAKING Horace C. Wright, Chicago, 111., aasignor to Chieago FlexibleShaft Company, Chicago, 111., a

corporation of Illinois Application September 3, 1936, Serial No. 99,223

'7 Claims.

This invention relates to sadirons and has special reference to a soleplate for sadirons and of a method for making the same.

The invention contemplates a sole plate of cavity. The main cavity isadapted to receive 15 a heating element and a retaining element asdisclosed in the copending application of Ivar Jepson, Serial No.38,533, filed August 30, 1935. In the past, the sole plates of thischaracter have been made from steel or malleable iron through 20 forgingoperations, which method has been satisfactory in some respects buthighly unsatisfactory in others. The cost of producing the sole platesin quantity has been high because of the close tolerances allowed in thesize of the cavity 25 which has resulted in a considerable proportion ofrejects. Even when the tolerances are maintained within the closestlimits with which the forging operation can be reasonably successful thevariation in the size of the cavity is such as 30 to introduce majordifficulties in the manufacture and assembly of the iron. Another sourceof serious trouble is in the fact that the forging operations must beconducted hot and, under the circumstances, there is a tendency towardthe 35 formation of scale and pits resulting from scale,

on the bottom surface of the cavity. Since the heat from the heatingelement must be carried across this face these irregularities have amaterial effect on the rate of heat transfer. More 40 than this,however, the presence of pits or points along the surface where theheating element cannot be pressed firmly against the surface results ina burning out of the heating element because in these small areas theheat is not properly con- 45 ducted away from the resistance wire of theheating element, causing the wire to become overheated and to fuse, thusopening the circuit through the element. 'I'heproduction of a sole plateof this character which would be free of 50 the defects enumerated on acommercially feasible basis has, therefore, been an important problem.

Among the objects of the invention is the provision of a generallyimproved sole plate of great- 56 er uniformity in production, of lowercost, of im- 'rected to Figure 1.

proved properties, and wherein the bottom of the cavity therein issmooth and bright, the dimensions of the cavity are consistently uniformand the side walls of the cavityare vertical with respect to the bottomthereof and the provision of a method for making the sole plate wherebycertain economies are effected and wherein the base plate and side wallsare independently formed and thereafter brazed together to form the soleplate.

Other objects and advantages will become apparent from the followingdescription and the accompanying drawing, in which- Figure 1 is anexpanded view showing the parts entering into the construction of thesole plate;

Fig. 2 is a perspective view of the finished sole plate;

Fig. 3 is a section on the line 3--3 of Fig. 2, and

Fig. 4 is a section on the line 4-4 of Fig.

The structure of the sole plate will be apparent from a description ofthe method for making the same when considered in connection with thedrawing and attention is, therefore, first di- A base plate designatedgenerally by the numeral 5 is first cut from a sheet of rolled metalhaving plane upper and lower faces. Advantageously this will be a sheetof cold rolled steel or other cold rolled metal, as in this manner thescale and pitting associated with hot working processes are avoided andthe sheet will, without further processing, have a smooth and brightupper and lower surface. In the present instance, the base plate 5 iscut from a sheet of about stock, this being the thickness desired in thecavity portion of thesole plate. The base plate 5 is then subjectedjo aswedging operation along. the upper edge or its periphery so as to bevelat least a portion of the edge thereof as shown at 6 through whichoperation a considerable amount of grinding is eliminated in thefinishing operations. The marginal side walls designated generally bythe numerals I and 8 are cut to length from a straight rod of stockwhich is rolled to the desired cross-sec-' 5 tional dimensions, asloping side as shown at 9 being rolled on the stock at the mill. Theserods are preferably made of cold rolled steel in the usual manner. Theside members 1 and 8 are then subjected to a forming operation throughwhich they are given a curvature conforming to the curvature of the sideof the base plate 5 so that when placed thereon the outer beveled sides9 will form a continuation of the beveled portion 8 of the base plateand the forward ends H and u l2 thereof will abut each other at theforward end of the base plate. A back wall member I3 is likewise cut tolength from rod stock which is cold rolled to the proper cross-sectionalshape and dimensions at the mill. This member may have a beveled side Mof the same or a different slopefrom the beveled side 9 and is adaptedto be interposed at the rear of the base plate 5 between the spaced endsof the side members I and 8 so that the side N forms a continuation ofthe rear edge of the base plate 5. The member I3 is, in this instance,drilled and tapped, as shown at l5, for the purpose ,of supporting otherparts of the iron structure. Rods l6 and I! also preferably of coldrolled steel, though not necessarily so, are cut to size to form theside walls for the thermostat well, as shown in Fig. 2. A block l8 whichmay be tapped and drilled, as shown at 19, is cut to size to beinterposed between the well walls l6 and I1 against thebase plate 5 forthe purpose, in this instance, of supporting a portion of the thermostat.mechanism. A boss 2| which is drilled and tapped, as shown at 22, iscut of somewhat greater height, in this instance, than the side walls Iand 8 and is adapted to be positioned with its end against the baseplate 5 in the manner shown in Fig. 2, thereby serving as an end wallfor the thermostat .well and for the purpose of attaching thesuper-structureof the iron. A second boss 23 having an annular shoulder24 adjacent its upper end is cut in a suitable manner and is of suchheight that the distance between the lower end thereof and the lowerface of the shoulder 24 is substantially equal to the height of the sidewalls I and 8, whereby when positioned in the manner shown in Fig. 2 theshoulder 24 overhangs and confines the upper edge of the side walls Iand 8.v

The elements are assembled together in the positions shown in Fig. 2 andare firmly held in these positions by any suitable means as, forexample, by spot-welding or by the use of a suitable jig. While I havesatisfactorily employed spot-welding for the purpose I prefer to employa jig, the particular structure of which forms no part of this inventionand is consequently not shown.

With the elements held or secured in the positions described, the partsare brazed together in a brazing furnace according to methods well knownin the art. The brazing operation involves the use of a brazing mediumwhich may consist of wire, chips, or paste, of a suitable brazing metalas is well known in the art. In this instance, I prefer to use wire asthe brazing medium which may be either copper wire or a wire made of acopper zinc alloy. This brazing medium is placed along the junction ofthe surfaces to be brazed and the assembled sole plate is passed througha brazing furnace. The brazing oven is of the well known type employingcontrol of the atmosphere in the furnace which are commonly known ascontrolled atmosphere furnaces, suitable types being manufactured by theGeneral Electric Company and The Electric Furnace Company. In thisfurnace the temperature of the sole plate assembly is brought to a pointat which the brazing medium becomes molten whereupon the molten metalflows through capillarity into the interface between the parts, theatmosphere in the furnace being controlled as to its chemical actionboth upon the sole plate and the brazing medium. As the sole plateassembly moves on through the brazing furnace the temperature isgradually reduced so that the brazing medium solidifies and thetemperature of the composite structure is reduced to a point at which itmay be removed from the furnace without detrimental effect.

The brazed sole plate is then removed from the jig, the annular bevelededges 25 are ground to smoothness and to the proper slope, the edges andthe bottom of the plate are polished and subsequently electro-platedaccording to the usual procedure in finishing sole plates of thischaracter.

The finished and plated sole plate as shown in Fig. 2, when assembled inthe iron cannot be distinguished from a sole plate made by the use ofthe foregoing operation. The sole plate is, however, characterized bythe smooth and bright bottom of the cavity 28, by the freedom of thisbottom from pits or scale, by the accurate inside dimensions of the pit26, and by the smooth vertical sides of the pit which meet the bottom ata sharp right angle. These properties are of material value in the soleplate in that the absence of pits or scale greatly reduces the number ofirons which become defective in use due to the buming out of the heatingelement. The smoothness and brightness of the surface substantiallyfacilitates the transfer of heat to the sole plate. The accuracy in thedimensions of the cavity permits the heating'element and the retainingelement subsequently inserted in the cavity to fit therein within closelimits and materially reduces the cost in that heating elements of asingle fixed size may be utilized in the assembly of the irons asdistinguished from the provision of a plurality of sizes differing fromeach other a small,

amount, as has been heretofore necessary to obtain a close fit.

Wholly aside from the improved properties of the sole plate the methodpermits of substantial reduction in the cost of manufacturing the soleplate since the various elements may be turned out by large scaleproduction methods and the various steps of the method may be conductedon a large scale production basis with a relatively small percentage ofrejected product. This is contrasted with the forging operations of theprior art in which the forging of this piece constitutes a verydifiicult forging operation because of the necessity of maintainingclose limits in size and the necessity for obtaining in the productionat least a reasonably smooth and scaleless surface at the bottom of thecavity. Material savings are also made in the finishing operations bythe reduction in the amount of grinding required to prepare the articlefor plating operations.

I am aware that numerous alterations and changes may be made in theinvention as herein described without departing from the spirit of theinvention and I do not wish to be limited except as required bythe priorart and the scope of the appended claims, in which- I claim:

1. The combination in a sole plate for sadirons, of a base platecomprising a fiat rolled metal sheet having smooth surfaces free frompits and scale, upstanding marginal preformed walls thereon of across-section to prevent Warpage of the base plate and defining a topcavity for the reception of a heating element between said walls, andmeans within the cavity for attaching the super-structure of an iron,the sole plate being characterized by the accurate dimensions of saidcavity, smoothness of the bottom of said cavity, and by the fact thatsaid elements are se- "cured in position by a capillary layer of brazingmaterial.

2. The method for making sadiron sole plates of the type having aheating element cavity and annular walls which includes the steps ofcutting a base plate from smooth, bright'stock of rolled cross-section,cutting peripheral side walls of required length from straight smoothstock, bending said walls to the required curvature, securing said partsin the desired relationship and thereafter brazing said parts togetherin a furnace.

3. A method for making sadiron sole plates comprising cutting a baseplate from a fiat sheet of smooth rolled metal, preshaping peripheralside walls for said plate, assembling said side walls on said plate toprovide a top cavity therein having a smooth bottom, and thereafterbrazing said parts together in a brazing furnace to produce successiveplates wherein'the size and shape of the cavities are maintained withinclose limits. 4. A method for making sadiron sole plates comprisingcutting a base plate from a flat sheet of rolled metal having a smoothscaleless surface, preshaping peripheral side walls and centrallydisposed walls for said plate from rolled metal, assembling said wallson said plate, applying a brazing medium to the junction between saidparts, and thereafter passing said assembly through a brazing furnacewhile retaining the parts in said position to produce successive platesin which the spaces between the walls are maintained uniform withinrelatively close limits.

5. A method for making sadiron sole plates comprising cutting a baseplate from a flat sheet of cold rolled steel, preshaping peripheralwalls for said plate from rods of predetermined rolled cross-sectionalshape, preshaping walls for a centrally disposed thermostat wall,forming attaching means for the super-structure of the iron, assemblingsaid parts in the desired relation, brazing said parts together in abrazing furnace while maintaining the parts in accurately fixed relationto produce uniformity of size in successive plates, and thereaftergrinding, polishing and plating the bottom and sides of the sole platethus produced.

6. The method for making sadiron sole plates comprising cutting a baseplate from a flat sheet of cold rolled steel, beveling the edges of saidbase plate to slope inwardly from bottom to top, preshaping peripheralwalls for said plate from rods having a beveled side rolled thereon, ofa slope substantially identical with the slope of the beveled edges onsaid base plate so that when placed together said bevels aresubstantially coplanar, assembling the side walls on said plate, andthereafter brazing said parts together in a brazing furnace.

'7. The combination in a sole plate for sadirons, of a base platecomprising a flat rolled metal sheet having smooth surfaces free frompits and scale, upstanding marginal walls or rolled section thereondefining a top cavity for the reception therein of a heating element,the base plate and walls being of a thickness to substantially resistwar-page of the sole plate in service, centrally disposed base walls onsaid plate within the cavity defining a thermostat well, and meanswithin the cavity for attaching the super-structure of an iron, the soleplate being characterized by the accurate dimensions of said cavity,smoothness of the bottom of said cavity, and by the fact that saidelements are secured in position by a capillary layer of brazing metal.

HORACE C. WRIGHT.

CERTIFICATE OF CO RRECTI ON Patent No. 2,158,720.

' HORACE 0.

November 29, 1958 WRIGHT.

It is hereby certified that error appears in the printedspecification ofthe above n b patent requiring correction as follows; Page}, secondcolumn, line 1, claim 5, for the word "wall" read well; and that thesaid Letters Patent should be read with this correction therein that thesame may conform to the record of the case in the Patent Office.-

Signed and sealed this 7th day of February, A. D. 1959.

(Seal) Henry Van arsdale Acting Commissioner of Patents.

